Spoken Language in Persons with Down Syndrome: A Life-Span Perspective

Abstract

The purpose of the present study is to review master and doctoral dissertations in the field of early childhood special education carried out in Turkey. Within the context of this study, 24 studies during early childhood were found in Turkey concerning children with developmental delays/disabilities, their parents and the services provided for them. The studies were analyzed in seven categories according to the subject covered. Nine studies in the category of teaching of skills, four studies in the category of preschool inclusion, three studies in the category of helping parents acquire skill of instructing their children, three studies in the category of comparing children with development delays with each others and peers with normal development, three studies in the category of examining mothers' emotional status, two studies in the category of services provided for children and one study in the category of describing a situation regarding children have been identified and reviewed.

Keywords

• Spoken language
• Down syndrome
• life-span

Down sendromlu bireyler konusunda konuşma dili: Yaşam boyu bakış açısı

Öz

Bu araştırmanın amacı, Türkiye'de erken çocuklukta özel eğitim alanında yapılan yüksek lisans ve doktora tezlerini incelemektir. Bu çalışma kapsamında, gelişimsel geriliği olan çocuklar, aileleleri ve onlara sağlanan hizmetlerle ilgili erken çocukluk dönemine ait Türkiye'de gerçekleştirilmiş 24 çalışma bulunmuştur. Bu çalışmalar kapsamda yer alan konulara göre yedi ayrı kategoride analiz edilmiştir. Beceri öğretimi kategorisinde dokuz çalışma, okul öncesinde kaynaştırma kategorisinde dört çalışma, çocuklarının eğitimiyle ilgili becerilerin aileler tarafından kazanılmasına yardım kategorisinde üç çalışma, gelişimsel geriliği olan çocukları birbirleriyle ve normal gelişim gösteren akranlarıyla karşılaştırılması kategorisinde üç çalışma, annelerin duygusal durumlarını inceleme kategorisinde üç çalışma, çocuklara sağlanan hizmetler kategorisinde iki çalışma ve çocuklarla ilgili bir durumu açıklama kategorisinden bir çalışma belirlenmiş ve incelenmiştir.

Anahtar Kelimeler

• Konuşma dili, Down sendromu, yaşam boyu

Kaynakça

1. Abbeduto, L., & Keller-Bell, Y. (2003). Pragmatic development and communication training. In J.A. Rondal & S. Buckley (Ed.), Speech and language intervention in Down syndrome (pp. 98-115). London: Whurr.
2. Abbeduto, L., & Rosenberg, S. (1992). The communication competence of mildly retarded adults. Applied Psycholinguistics, 1, 405-426.
3. Abbeduto, L., Davies, B., Solesby, S., & Furman, L. (1991). Identifying the referents of spoken messages: Use of context and clarification request by children with and without mental retardation. American Journal of Mental Retardation, 95, 551-562.
4. Baddeley, A. (1980). Human memory. Hillsdale, New Jersey: Erlbaum.
5. Barrett, M., & Diniz, F. (1989). Lexical development in mentally handicapped children. In M. Beveridge, G. Conti-Ramsden, & I. Leudar (Eds.), Language and communication in mentally handicapped people (pp. 3-32). London: Chapman and Hall.
6. Benda, C. (1949). Mongolism and cretinism. New York: Grune & Startton.
7. Berry, P., Groenweg, G., Gibson, D., & Brown, R. (1984). Mental development of adults with Down‘s syndrome. American Journal of Mental Deficiency, 89, 252-256.
8. Bowler, D., Cufflin, J., & Kiernan, C. (1985). Dichotic listening of verbal and nonverbal material by Down‘s syndrome children and children of normal intelligence. Cortex, 21, 637-644.

9. Boysson-Bardies, B., de (1996). Comment la parole vient aux enfants. Paris: Jacob.
10. Bray, M., & Woolnough, L. (1988). The language of children with Down‘s syndrome aged 12 to 16 years. Child Language Teaching and Therapy, 4, 311-321.
11. Brent, M., & Siskind, J. (2001). The role of exposure to isolated words in early vocabulary development. Cognition, 81, 833-844.
12. Buckley, S. (1999). Bilingual children with Down‘s syndrome. Down syndrome: News and Update, 1, 29-30.
13. Buckley, S. & Sacks, B. (1987). The adolescent with Down’s syndrome — Life for the teenager teaching and the family. Portsmouth, United kingdom: Portsmouth Down‘s syndrome Trust.
14. Carr, J. (1994). Long-term outcome for people with Down‘s syndrome. Journal of Child Psychology and Psychiatry, 35, 425-439.
15. Cichetti, D., & Beeghly, M. (1990). An organizational approach to the study of Down‘s syndrome: Contribution of an integrative theory of development; In D. Cichetti & M. Beeghly (Eds.), Children with Down syndrome: A developmental perspective (pp. 29-62). New York: Cambridge University Press.
16. Chapman, R. (1995). Language development in children and adolescents with Down‘s syndrome. In P. Fletcher & B. McWhinney (Eds.), The handbook of child language (pp. 641-663). Oxford: Blackwell.
17. Chapman, R. (2003). Language and communication in individuals with Down syndrome. In L. Abbeduto (Ed.), Language and communication in mental retardation (pp. 1-34).
18. Chapman, R., Schwartz, S., & Kay-Raining Bird, E. (1991). Language skills of children and adolescents with Down‘s syndrome: I. Comprehension. Journal Speech and Hearing Research, 34, 1106-1120.
19. Chapman, R., Schwartz, S., & Kay-Raining Bird, E. (1992, August). Language production of children and adolescents with Down’s syndrome. Paper presented at the 9th World Congress of the International Association for the Scientific Study of Mental Deficiency. Gold Coast, Australia (unpublished).
20. Chapman, R., Seung, H., Schwartz, S., & Kay-Raining Bird, E. (1998). Language skills of children and adolescents with Down syndrome: Production deficits. Journal of Speech and Hearing Research, 41, 861-873.
21. Cichetti, D., & Beeghly, M. (1990). An organizational approach to the study of Down‘s syndrome: Contributions to an integrative theory of development; In D. Cichetti & M. Beeghly (Eds.), Children with Down’s syndrome: A developmental perspective (pp. 29-62). New York: Cambridge University Press.
22. Clark, C., Edwards, J., & Smallpiece, V. (1961). Trisomy 21 normal mosaicism in an intelligent child with some mongoloid characters. Lancet, 1028-1030.
23. Coggins, T. (1979). Relational meaning encoded in two-word utterance of stage 1 in Down‘s syndrome children. Journal of Speech and Hearing Research, 22, 166-178.
24. Comblain, A. (1994). Working memory in Down‘s syndrome: Training rehearsal strategy. Down Syndrome Research and Practice, 2, 123-126.
25. Comblain, A. (1995). Batterie pour l’évaluation de la morpho-syntaxe. Laboratory for Psycholinguistics, University of Liège, Belgium (unpublished).
26. Comblain, A. (1996). Mémoire de travail et langage dans le syndrome de Down. Unpublished doctoral dissertation, University of Liège, Belgium.
27. Conners, F. (2003). Phonological working memory difficulty and related interventions. In J.A. Rondal & S. Buckley (Eds.), Speech and language intervention in Down syndrome (pp. 31-48). London: Whurr.
28. Cunningham, C., & Sloper, P. (1984). The relationship between maternal ratings of first word vocabulary and Reynell language scores. British Journal of Educational Psychology, 54, 160-167.
29. Curtiss, S. (1989). Abnormal language acquisition and the modularity of language. In F. Newmeyer (Ed.), Linguistics: The Cambridge survey (Vol. 2, pp. 96-116). Cambridge, United Kingdom: Cambridge University Press.
30. Das, J.P., Divis, B., Alexander, J., Parrila, R., & Naglieri, J. (1995). Cognitive decline due to aging among persons with Down syndrome. Research in Developmental Disabilities, 16 (6), 461-478.
31. Devenny, D., Hill, A., Patxot, D., Silverman, W., & Wisniewsky, H. (1992). Ageing in higher functioning adults with Down‘s syndrome: A longitudinal study. Journal of Intellectual Disability Research, 36, 241-250.
32. Devenny, D., Silverman, W., Hill, A., Jenkins, E., Sersen, E., & Wisniewski, H. (1996). Normal ageing in adult with Down‘s syndrome: A longitudinal study. Journal of Intellectual Disability Research, 40, 208-221.
33. Dodd, B. (1976). A comparison of the phonological systems of mental-age-matched severely subnormal and Down‘s syndrome children. British Journal of Disorders of Communication, 11, 27-42.
34. Dodd, B., & Leahy, Y. (1989). Phonological disorders and mental handicap. In M. Beveridge, G., Conti-Ramsden, & Y. Leudar (Eds.), Language and communication in mentally handicapped people (pp. 33-56). London: Chapman & Hall.
35. Duchan, J.F., & Erickson, J.G. (1976). Normal and nonretarded children‘s understanding of semantic relations in different verbals contexts. Journal of Speech and Hearing Research, 19, 767-776.
36. Dykens, E., Hodapp, R., Finucane, B. (2000). Genetics and mental retardation syndromes: A new look at behavior and interventions. Baltimore, MD: Brookes.
37. Eilers, R., Bull, D., Oller, K., & Lewis, D. (1985). The discrimination of rapid spectral speech cues by Down syndrome and normally developing infants. In S. Harel & N. Anastasiouw (Eds.), The at-risk infant. Psycho/social/medical aspects (pp. 115-132). Baltimore, Maryland: Brookes.
38. Eimas, P. (1996). The perception and representation of speech by infants. In J. Morgan & K. Demuth (Eds.), Signals of syntax (pp.25-39). Mahwah, New Jersey: Erlbaum.
39. Elliott, D;, Weeks, D., & Elliott, C (1987). Cerebral specialization in individuals with Down syndrome. American Journal of Mental Retardation, 92, 263-271.
40. Feltmate, K, & Kay-Raining Bird, E. (2008). Language learning in four bilingual children with Down syndrome. A detailed analysis of vocabulary and morphosyntax. Canadian Journal of Speech-Language Pathology and Audiology, 32(1), 6-20.
41. Fenner, M., Hewitt, K., & Torpy, D. (1987). Down‘s syndrome: Intellectual and behavioural functioning during adulthood. Journal of Mental Deficiency Research, 31, 241-249.
42. Fishler, K., & Koch, R. (1991). Mental development in Down‘s syndrome mosaicism. American Journal on Mental Retardation, 96, 345-351.
43. Fowler, A. (1988). Determinants of rate of language growth in children with Down‘s syndrome. In L. Nadel (Ed.), The psychobiology of Down’s syndrome (pp. 217-245). Cambridge, Massachusetts: MIT Press.
44. Fowler, A., Gelman, R., & Gleitman, L. (1994). The course of language learning in children with Down‘s syndrome. In H. Tager-Flusberg (Ed.), Constraints on language acquisition. Studies of atypical children (pp. 91-140). Hillsdale, NJ: Erlbaum.
45. Franceschi, G. (1988). Pronto invecchiamento nella sindrome di Down. Contribution at the Symposium Il progredire nell’età nella persona con ritardo mentale, Università degli Studi di Urbino, Italy (unpublished).
46. Gathercole, S., & Baddeley, A. (1993). Working memory and language. Hillsdale, New Jersey: Erlbaum.
47. George, M., Thewis, B., Van der Linden, M., Salmon, E., & Rondal, J.A. (2001). Elaboration d‘une batterie d‘évaluation des fonctions cognitives de sujets âgés porteurs d‘un syndrome de Down. Revue de Neuropsychologie, 11 (4), 549-579.
48. Gibson, D. (1981). Down’s syndrome: The psychology of mongolism. Cambridge, United Kingdom: Cambridge University Press.
49. Golinkoff, R., Mervis, C, & Hirsh-Pasek, K. (1994). Early object labels in the case for a developmental lexical principles framework. Journal of Child Language, 21,125-155.
50. Halliday, M. (1985). An introduction to functional grammar. London: Arnold.
51. Hodapp, R., & Dykens, E. (2004). Genetic and behavioural aspects: Application to maladaptive behaviour and cognition. In J.A. Rondal, R. Hodapp, S. Soresi, E. Dykens, & L. Nota, Intellectual disabilities. Genetics, behaviour and inclusion (pp. 13-48). London: Whurr.
52. Hodapp, R., Evans, D., & Gray, F. (1999). Intellectual development in children with Down syndrome; In J.A. Rondal, J. Perera & L. Nadel (Eds.), Down syndrome. A review of current knowledge (pp. 124- 132). London: Whurr.
53. Jarrold, C., & Baddeley, A. (1997). Short-term memory for verbal and visuospatial information in Down‘s syndrome. Cognitive Neuropsychiatry, 2, 101-122.
54. Jarrold, C., Baddeley, A., & Phillips, C. (1999). Down syndrome and the phonological loop: The evidence for an important verbal short-term memory deficit. Down Syndrome Research and Practice, 6, 61-75.
55. Jusczyk., P., Cutler, I., & Redanz, N. (1993). Infants‘ preference for the predominant stress patterns of English words. Child Development, 64, 675-687.
56. Kaufman, A., & Kaufman, N. (1993). Batterie pour l’Examen Psychologique de l’Enfant. Paris: Editions du Centre de Psychologie Appliquée.
57. Kay-Raining Bird, E. (2006). The case for bilingualism in children with Down syndrome. In R. Paul (Ed.), Language disorders from a developmental perspective. Essays in honor of Robin S. Chapman (pp. 249-275). Mahwah, New Jersey: Erlbaum.
58. Kay-Raining Bird, E., Cleave, P., Trudeau, N., Thornadottir, E., Sutton, A., & Thorpe, A. (2005). The language abilities of bilingual children with Down syndrome. American Journal of Speech-Language Pathology, 14, 187-199.
59. Layton, T., & Sharifi, H. (1979). Meaning and structure of Down‘s syndrome and nonretarded children spontaneous speech. American Journal of Mental Deficiency, 83, 139-445.
60. Leifer, J., & Lewis (1984). Acquisition of conversational response skills by young Down syndrome and nonretarded young children. American Journal of Mental Deficiency, 88, 610-618.
61. Lenneberg, E. (1967). Biological foundations of language. New York: Wiley.
62. Lenneberg, E., Nichols, L., & Rosenberger, E. (1964). Primitive stages of development in mongolism. In D. McRioch & A. Weinstein (Eds.), Disorders of communication (pp. 119-137). Baltimore, Maryland: Williams & Wilkins.
63. Mackenzie, S., & Hulme, C. (1987). Memory span development in Down‘syndrome, severely subnormal and normal subjects. Cognitive Neurospsychology, 4, 303-319.
64. Marcell, M., & Armstrong, V. (1982). Auditory and visual sequential memory of Down syndrome and nonretarded children. American Journal of Mental Deficiency, 87, 86-95.
65. Marcell, M., & Weeks, S. (1988). Short-term memory difficulties and Down‘s syndrome. Journal of Mental Deficiency Research, 32, 153-162.
66. Marcus, G., Vijayan, S, Bandi Rao, S., & Vishton, P. (1999). Rule learning by seven month-old infants. Science, 283, 77-80.
67. Markman, E. (1990). Constraints children place on word meanings. Cognitive Science, 14, 57-77.
68. Mayberry, R., Fisher, S., & Hatfield, N. (1983). Sentence repetition in American Sign Language. In J. Kyle and B. Woll (Eds.), Language in sign: International perspective on sign language (pp. 206-214). London: Croom Helm.
69. Menn, L. (1983). Development of articulatory, phonetic, and phonological capabilities. In B. Butterworth (Ed.), Language production (Vol. 2, pp. 3-50). New York: Academic Press.
70. Mervis, C. (1987). Child-basic object categories and early lexical development. In U.
71. Neisser (Ed.), Concepts and conceptual development: Ecological and intellectual factors in categorization (pp. 201-233). Cambridge, United Kingdom: Cambridge University Press.
72. Mervis, C. & Becerra, A. (2003). Lexical development and intervention. In J.A. Rondal & S. Buckley (Eds.), Speech and language intervention in Down syndrome (pp.63-85). London: Whurr.
73. Mervis, C., & Bertrand, J. (1994). Acquisition of the novel name-nameless category principle. Child Development, 65, 1646-1662.
74. Mervis, C., & Bertrand, J. (1995). Acquisition of the novel name-nameless category principle by young children who have Down syndrome. American Journal of Mental Retardation, 100, 231-243.
75. Miezejeski, C., Hearney, G., Belser, R., & Sersen, E. (1994). Aberrant lateralization of brainstem auditory evoked responses by individuals with Down syndrome. American Journal of Mental Retardation, 98, 481-489.
76. Montague, J;, & Hollien, H. (1973). Perceived voice quality disorders in Down‘s syndrome. Journal of Communication Disorders, 6, 76-87.
77. Moss, S., Tomoeda, C., & Bayles, K. (2000). Comparison of the cognitive linguistic profiles of Down syndrome adults with and without dementia to individuals with Alzeimer‘s desease. Journal of Medical Speech Language Pathology, 8, 69-81.
78. Mundy, P., Seibert, J., & Hogan, A. (1984). Relationship between sensorimotor and early communication abilities in developmentally delayed children. Merill Palmer Quarterly, 30, 33-48.
79. Nazzi, T., Bertoncini, J., & Mehler, J. (1998). Language discrimination by newborns: Towards an understanding of the role of rythm. Journal of Experimental Psychology: Human Preception and Performance, 24, 1-11.
80. Nazzi, T., Jusczyk, P., & Johnson, E. (2000). Language discrimination by English-learning 5-month-olds: Effects of rhythm and familiarity. Journal of Memory and Language, 43, 1-19.
81. Otomo, K. (2001). Maternal responses to word approximations in Japanese children‘s transition to language. Journal of Child Language, 28, 29-57.
82. Owings, N., McManus, M., & Scherer, N. (1981). A deinstitutionalized retarded adult‘s use of communication functions in a natural setting, British Journal of Disorders of Communication, 16, 119-123.
83. Ploog, D. (1984). Comment on J. Leiber‘s paper. In R. Harre & V. Reynolds (Eds.), The meaning of primate signals (pp. 88). Cambridge, United Kingdom: Cambridge University Press.
84. Prasher, V. (1996). Age-associated functional decline in adults with Down‘s syndrome. European Journal of Psychiatry, 10, 129-135.
85. Pueschel, S. (1995). Caracteristicas fisicas de las personas con syndrome de Down. In J. Perera (Ed.), Especificidad en el sindrome de Down (pp. 53-63). Barcelona: Masson.
86. Pueschel, S., & Sustrova, M. (1996). Visual and auditory perception in children with Down syndrome. In J.A. Rondal, J. perera, L. Nadel, & A. Comblain (Eds.), Down’s syndrome: Psychological, psychobiological and socio-educational perspectives (pp. 53-63). London: Whurr.
87. Reilly, J., Klima, E., & Bellugi, U. (1991). Once more with feeling: Affect and language in atypical populations. Development Psychopathology, 2, 367-391.
88. Ribes, R., & Sanny, J. (2000). Declive cognitivo en memoria y lenguaje: Indicadores del proceso de envejecimiento psicologico en la persona con sindrome de Down. Revista Sindrome de Down, 17, 54-59.
89. Rondal, J.A. (1975). Développement du langage et retard mental: Une revue critique de la littérature en langue anglaise. L’Année Psychologique, 75, 513-547.
90. Rondal, J.A. (1978). Maternal speech to normal and Down‘s syndrome children matched for mean length of utterance. In E. Meyers (Ed.), Quality of life in severely and profoundly mentally retarded people: Research foundations for improvement (pp.193-265). Washington, D.C.: American Association on Mental Deficiency, Monograph Series n°3.
91. Rondal, J.A. (1984). Linguistic development in mental retardation. In J. Dobbing, A.D.B. Clarke, J. Corbett, J. Hog, & R. Robinson (Eds.), Scientific studies in mental retardation (pp. 323-345). London: The Royal Society of Medicine and Macmillan.
92. Rondal, J.A. (1985). Langage et communication chez les handicapés mentaux. Bruxelles: Mardaga.
93. Rondal, J.A. (1995). Exceptional language development in Down syndrome. New York: Cambridge University Press.
94. Rondal, J.A. (2001). Lo sviluppo del linguaggio nella trisomia 21. Ciclo Evolutivo e Disabilità, 4 (2), 195-205.
95. Rondal, J.A. (2003a). Atypical language development in individual with mental retardation: Theoretical implications. In L. Abbeduto (Ed.), Language and communication in mental retardation. International Review of Research in Mental Retardation (Vol. 27, pp. 281-308). New York: Academic Press.
96. Rondal, J.A. (2003b). Bilingual and multilingual issues. In J.A. Rondal & S. Buckley (Eds.), Speech and language intervention in Down syndrome (pp. 195-205). London: Whurr.
97. Rondal, J.A. (2006). Expliquer l’acquisition du langage. Caveats et perspectives. Hayen (Sprimont, Belgique) : Mardaga.
98. Rondal, J.A. (2009). Psycholinguistique du handicap mental. Marseille: Solal.
99. Rondal, J.A., & Comblain, A. (1996). Language in adults with Down syndrome. Down syndrome Research and Practice, 4, 3-14.
100. Rondal, J.A., & Comblain, A. (2002). Language in ageing persons with Down syndrome. Down Syndrome Research and Practice, 8(1), 1-19.
101. Rondal, J.A., & Docquier, L. (2006). Maternal speech to down syndrome children. An update. Journal of Speech and Language and Applied Behavior Analysis, 1(2), 218-227.
102. Rondal, J.A., & Edwards, S. (1997). Language in mental retardation. London: Whurr.
103. Rondal, J.A., Elbouz, M., Ylieff, M., & Docquier, L. (2003). Françoise, a fifteen-year follow up. Down Syndrome Research and Practice, 8 (3), 89-99.
104. Rondal, J.A., & Lambert, J.L. (1983). The speech of mentally retarded adults in a dyadic communication situation: Some formal and informative aspects. Psychologica Belgica, 23, 49-56.
105. Rondal, J.A., Lambert, J.L., & Sohier, C. (1980). L‘imitation verbale et non verbale chez l‘enfant retardé mental mongolien et non mongolien. Enfance, 3, 107-122.
106. Rondal, J.A., & Perera, J. (2006). Down syndrome. Neurobehavioural specificity. Chichester, United Kingdom: Wiley.
107. Rondal, J.A., & Quiros Ramirez, A. (2007). Théorie de l‘esprit et langage: convergence entre les syndromes autistique, X-fragile, et d‘Asperger. Glossa, 101, 10-14.
108. Rondal, J.A., Thibaut, J.P., & Cession, A. (1990). Transitivity effects on children‘s sentence comprehension. European Bulletin of Cognitive Psychology, 10, 385-400.
109. Rosch, E. (1978). Human categorization. In N. Warren (Ed.), Advances in Crosscultural Psychology (Vol. 1, pp. 122-148). Hillsdale, New Jersey: Erlbaum.
110. Rosenberg, S., & Abbeduto, L. (1993). Language and communication in mental retardation. Development, process and intervention. Hillsdale, New Jersey: Erlbaum.
111. Rosin, M., Swift, E., & Bless, D. (1987, May). Communication profiles of people with Down’s syndrome. Communication presented at the Annual Convention of the American Speech and Hearing Association, New Orleans (unpublished).
112. Rosin, M., Swift, E., & Bless, D., & Vetter, D. (1988). Communication profiles of adolescents with Down‘s syndrome. Journal of Childhood Communication Disorders, 12, 49-64.
113. Ryan, J. (1975). Mental subnormality and language development. In E. Lenneberg (Ed.), Foundations of language development: A multidisciplinary approach (Vol. 2, pp.269-277). New York: Wiley.
114. Safran, J., Aslin, R., & Newport, E. (1996). Statistical learning by 8-month-old infants. Science, 274, 1926-1928.
115. Scherer, N., & Owings, N. (1984). Learning to be contingent: Retarded children‘s responses to their mothers‘ requests. Language and Speech, 27, 255-267.
116. Shi, R., Werker, J., & Morgan, J. (1999). Newborn infants‘ sensitivity to perceptual cues to lexical and grammatical words. Cognition, 72, B-11-B21.
117. Smith, B., & Oller, K. (1981). A comparative study of pre-meaningful vocalizations produced by normally developing and Down‘s syndrome infants. Journal of Speech and Hearing Disorders, 46, 46-51.
118. Smith, B., & Stoel-Gammon, C. (1983). A longitudinal study of the development of stop consonant production in normal and Down‘s syndrome children. Journal of Speech and Hearing Disorders, 48, 114-118.
119. Spitzer, R., Rabinowitch, J., & Wybar, K. (1961). A study of the abnormalities of the skull, teeth and lenses in mongolism. Canadian Medical Association Journal, 82,567-572.
120. Stoel-Gammon, C. (2003). Speech acquisition and approaches to intervention. In J.A. Rondal & S. Buckley (Eds.), Speeech and language intervention in Down syndrome (pp. 49-62). London: Whurr.
121. Tager-Flusberg, H. (1986). Constraints on the representation of word meaning: Evidence from autistic and mentally retarded children. In S. Kuczaj and M. Barrett (Eds.), The Development of word meaning (pp. 69-81). New York: Springer.
122. Thordadottir, E., Chapman, R., & Wagner, L. (2002). Complex sentence production by adolescents with Down syndrome. Applied Psycholinguistics, 23 (2), 163-183.
123. Tristao, R., & Feitosa, M. (2002). Use of visual habituation paradigm to investigate perception in Down syndrome infants. Proceedings of the International Society for Psychophysics, 18, 552-557.
124. Vallar, G., & Papagno, C. (1993). Preserved vocabulary acquisition in Down‘s syndrome. The role of phonological short-term memory. Cortex, 14, 89-101.
125. Van Borsel, J. (1988). An analysis of the speech of five Down‘s syndrome adolescents. Journal of Communication Disorders, 21, 409-422.
126. Van Borsel, J. (1993). De articulatie bij adolescenten en volwassenen met het syndroom van Down. Doctoral dissertation, Vrije Universiteit Brussels, Brussels. (unpublished).
127. Van Buggenhout, G., Lukusa, T., Trommelen, J., De Bal, C., Hamel, B., & Fryns, J.-P. (2001). Une étude pluridisciplinaire du syndrome de Down dans une population résidentielle d‘arriérés mentaux d‘âge avancé: Implications pour le suivi médical. Journal de la Trisomie 21, 1 (2), 7-13.
128. Waxman, S, & Booth, A. (2001). Seeing pink elephants : Fourteen-month-olds‘ interpretations of novel nouns and adjectives. Cognitive Psychology, 43, 217-242.
129. Wilson, B., Ivani-Chalian, R., & Aldrich, F. (1991). The Child Rivermead Behavioural Memory Test. London: Thames Valley Test Company.
130. Zetlin, A., & Sabsay, S. (1980, March). Characteristics of verbal interaction among moderately retarded peers. Paper presented at the Gatlinburg Conference on Research in Mental Retardation, Gatlinburg, Tennessee (unpublished).